While she had only competed in ten races during her first World Cup winter, Neuner became a fixture in the German team in the 2006–07 season. She proved to be one of the fastest cross-country skiers in biathlon, and at 19 years old, regularly set the fastest course times. On 5 January 2007, Neuner won her first World Cup event, the sprint race in Oberhof, Germany. Her victory on home soil, before a crowd of 19,000 people, received considerable media attention and put her into the national spotlight for the first time. Two days later at the pursuit race, she forgot to reload her rifle after warm-up. She was handed a new magazine during the prone shooting and managed to finish third despite a total of six shooting errors.
Neuner was scheduled to compete at the junior world championships in 2007. However, following her first World Cup win, she was instead appointed for the senior World Championships in Antholz, Italy. On 3 February 2007, she won gold in the sprint, beating Sweden's Anna Carin Olofsson by 2.3 seconds. It was her first world championship event ever and only her second victory at senior level. One day later, she also claimed the pursuit title, in spite of four shooting errors. Following a 14th place in the mass start, Neuner, alongside Martina Beck, Andrea Henkel and Kati Wilhelm, also won gold in the relay race on 11 February 2007. With three titles, she was the championship's most successful athlete and became the youngest triple world champion.
At the end of the season, she continued her successful run with four more World Cup wins. In March 2007, Neuner won the pursuit and mass start races at Holmenkollen in Oslo, Norway, and she won the sprint and pursuit events at the season final in Khanty-Mansiysk, Russia, giving her seven career World Cup wins. She ended her first complete season fourth in the Overall World Cup standings and finished second in the pursuit discipline. In the course of three months, Neuner had emerged from anonymity to become one of Germany's most popular female athletes. At the end of 2007, she had earned an estimated 1.3 million euros through sponsorship and endorsement deals.
After missing the podium at the 2007–08 season's first two World Cups, Neuner was part of Germany's winning relay team in Pokljuka, Slovenia in December 2007. She claimed her eighth World Cup win at the mass start in Oberhof in January 2008, and later that month won the relay race in Ruhpolding with the German team. Shortly before her 21st birthday, Neuner decided to again compete at the Junior/Youth World Championships, held in Ruhpolding in January 2008—the last time she was eligible to enter. She won gold in the sprint and the pursuit, but withdrew from the individual race to prepare for the senior world championships alongside her German team mates.
Neuner has won 6 races (all sprints) with a perfect shooting record: Khanty-Mansiysk sprint in March 2007, 2011 World Championship sprint and 4 sprints in her final 2011–12 season. She also shot clean on two other occasions, the sprint in Kontiolahti in March 2006, coming in fourth place, and the Östersund sprint in December 2008, finishing third. Her worst shooting performance came in December 2008, with a total of nine shooting errors at the World Cup pursuit in Hochfilzen. Neuner's costliest shooting occurred during a mass start race in Antholz in January 2009. After 15 clean shots, she was leading by 53.6 seconds before the final shooting, in which she missed all five targets, eventually dropping to sixth place.
Biathlon is the most popular winter sport in Germany. Each World Cup event is shown live on German television and the January World Cup races in Oberhof, Ruhpolding and Antholz are regularly seen by over five million viewers. Following her three world championship titles in 2007, Neuner quickly became one of Germany's most popular female sport stars, often nicknamed "Gold Lena" in the media. During her first two years in the spotlight she signed several endorsement deals and claimed numerous awards. Neuner's popularity grew further with her success during the 2010 Winter Olympics. Her second gold medal win in the Olympic mass start was seen live by 9.75 million television viewers (a 31.5 per cent market share), the most watched programme of the Games in Germany. Her withdrawal from the Olympic relay was one of the dominating stories of the Winter Olympics in Germany, leading to much media speculation whether pulling out had been entirely her decision. She later received the Fair Play medal of Germany's Olympic Society for setting an example of "team spirit".
Neuner won the Biathlon Award, chosen by the national coaches of the World Cup teams, for Female Athlete of the Year in both 2007 and 2008, and she was awarded the Goldener Ski (Golden Ski), the highest award of the German Ski Association in 2007, 2008 and 2010. The Forum Nordicum, a consortium of journalists form twelve countries, named her Biathlete of the Year in the 2007–08 and 2009–10 seasons, beating out her male counterparts Ole Einar Bjørndalen and Emil Hegle Svendsen respectively. Neuner was chosen as Germany's 2007 Sportswoman of the Year by the country's sports journalists. The following years, she came in third for the 2008 award and was voted in second place in 2010. Along with all Olympic medal winners, she received the Silberne Lorbeerblatt (Silver Laurel Leaf) in 2010, the highest state decoration for athletes in Germany. In 2011, readers of Germany's top selling newspaper Bild voted Neuner the seventh greatest German sportsperson of all time, and she was again named German Sportswoman of the Year. Nine months after her retirement, Neuner received Germany's Sportswoman of the Year award for a third time.
Neuner's interest in knitting has often been addressed by the German media and she maintains a knitting website, which includes detailed knitting instructions and a "knitting blog". She has stated that she usually takes knitting equipment on her travels during the season and that knitting is a way for her to relax. In 2007, Neuner declined an offer to appear nude in the German edition of Playboy. Outside of Germany, she is particularly popular in Russia, where she has a fan club and from where she has said to receive half of her fan mail. In 2010, Neuner appeared in an advertising campaign for a lingerie line. She explained she tried to use it in a deliberate attempt to correct her media image, after becoming irritated with her public persona of "little sweet Lena". She was an ambassador for the 2011 FIFA Women's World Cup in Germany. and a member of the board of trustees for Munich's bid to host the 2018 Winter Olympics.